More than ever before teachers, principals, and superintendents are joining with parents and citizens of the community in examining and appraising what the schools are trying to do and how their work can be adequately supported. One of the topics that comes up for frequent discussion in the high school field is the Carnegie Unit. It has been our experience that very few people in or out of high school know the story of the Carnegie Unit. The purpose of this bulletin is to explain in detail the origin, status, and trends. The chapters are as follows: (1) Introduction and purpose of study; (2) History of the Carnegie Unit; (3) The present role of the Carnegie Unit in secondary education; (4) Efforts to improve or displace the Carnegie Unit; and (5) Summary: The case for and against the Carnegie Unit. [Best copy available has been provided.]